1. Technical Field
This invention relates generally to tubular sleeve assemblies that provide thermal protection to an electronic object contained therein, and more particularly to a tubular sleeve assembly including a positioning member to maintain the assembly in a selectively releasable, fixed position about the electronic object contained therein.
2. Related Art
Sensors used in automotive applications, such as oxygen sensors which provide data to control engine operation and performance, are often mounted within the engine compartment of a vehicle where they are subject to harsh environmental elements including intense radiant heat, sources of abrasion and vibration during vehicle operation. Due to the harsh environmental elements, it is advantageous, and in many cases a requirement, to cover the relatively delicate, temperature sensitive sensors with protective sleeving in an effort to dampen vibration, provide protection against abrasion and shield radiant heat from reaching the sensor. Such sleeves generally comprise an elongated, cylindrical tube extending between opposite, open free ends. The cylindrical tube includes a damping inner layer of a nonwoven material, for example, polyester felt and a reflective outer layer comprising, for example, an aluminum foil layer laminated to an outer surface of the inner layer.
Due to the configuration of the aforementioned protective cylindrical sleeve and its harsh environment, it is typically difficult to assemble the sleeve about the sensor and elongate wire harness connected thereto in a manner which allows the sleeve to be reliably secured and maintained in a desired position, while at the same time being readily removable for servicing of the sensor. Adhesives, tape and interference fits of an entirety of an inner surface of the cylindrical wall of the sleeve are used to effect attachment to the wire harness and to the sensor, but each of these mechanisms suffer various disadvantages. Adhesive attachment of the sleeve about the sensor, while generally secure, at least initially, permanently attaches the sleeve to the sensor, and thus, complicates servicing the sensor at a future time, and in addition, the adhesives can breakdown over time, thereby causing the sleeve to become dislodged from its desired protective position about the sensor. As a result, while in its initially bonded position, this method does not allow for easy removal of the sleeve for servicing of the sensor or reuse of the sleeve, as it requires destroying the bond joint of the adhesive. In addition, tape and interference fits can be unreliable in view of the heat and vibration encountered within the engine compartment, with tapes further being particularly burdensome to apply. Further, friction fits of an entirety of a sleeve inner surface suffer from variances in component tolerances, and difficulty of assembly, particularly if the interference is too great, or if the sleeve needs to traverse increased diameter obstacles along the path of assembly, such as a connector, for example. Further mechanisms are also known, such as using end caps made from separate materials from the tubular sleeve to position the sleeve about an elongate member of a fixed, predetermined diameter, wherein the end cap facilitates locating and maintaining the tubular sleeve in its intended position about the wire harness. Although generally effective in locating and maintaining the tubular sleeve in its assembled position, known end caps are typically suitable for use about wire harness having a specific diameter, and thus, they are not useable over a range of wire harness diameters, thereby requiring differently sized end caps for different applications.